Well, for us non-believers, how are we supposed to tell the difference?...From the non-believer's perspective it all looks about the same frankly.
Good question. It's not difficult to tell the difference but it does take some effort. The most respectful way to compare the two is to do what I did, which is to read the scriptures of the two religions (you should be able to borrow a copy of the Koran from a public library). It won't take you more than a couple of hours to see many fundamental differences.
Again, how so? Neither Koran nor Bible demonstrate the existence of any God in my opinion. So which one do I go with and why?